1. Field of the Invention
The present invention generally relates to accessing records documenting a business problem in document databases. More particularly, the present invention relates to implementing a relational schema between a plurality of interconnected entities in a hierarchical database.
2. Description of the Related Art
Databases are computerized information, storage and retrieval systems. Storing and retrieving data in a database is performed by means of a computer database management system (DBMS). Depending on how data is modeled by a database, different types of databases are differentiated.
The most prevalent type of database is the relational database, a tabular database in which data is defined so that it can be reorganized and accessed in a number of different ways. Data records in a relational database are maintained in tables, which are a collection of rows all having the same columns. Each row represents a data record and each column maintains information on a particular type of data for the data records that comprise the rows. Data records may be indexed using unique indices or keys that join different data records in different related tables together.
Another important type of database is the hierarchical database. The hierarchical database uses a hierarchical schema for storing information known as the parent/child model. A hierarchical schema may be represented as a tree structure, where each parent node may have a plurality of child nodes, while each child node may only have one parent node. Examples for hierarchical databases are IMS and Lotus Notes from International Business Machines of Armonk, N.Y.
Lotus Notes integrates a number of today's most important information sources that the user may seamlessly access on-line or off-line. Among others, Lotus Notes integrates an e-mail, calendaring, group scheduling, instant messaging, security, workflow, accessibility and cross split form capability. As a result of their diverse functionality, hierarchical databases such as, Lotus Notes, are widely spread and used by a large number of users, including a number of Fortune 500 companies.
A major disadvantage of hierarchical databases is that they are not suitable for implementing solutions to problems involving a relational schema. Consequently, users of hierarchical databases in general are required to use relational databases when trying to implement relational schemas.
Accordingly, there is a need to adapt hierarchical databases for use with relational schemas.